Question

The ΔH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kJ/mol. When a 13.9 g sample of NaOH dissolves in 250.0 g of water in a coffee-cup calorimeter, the temperature increases from 23.0°C to ________°C. Assume that the solution has the same specific heat as liquid water: 4.18 J/g•°C.

Answer 1

How much heat(q) does the NaOH provide? That is 44.4 kJ/mol or 44.4 kJ/40 g and you have 13.9 g; therefore, q = 44,400 x (13.9/40) = ??
Then q = mass water x specific heat water x (Tfinal-Tinitial). Solve for Tfinal. The answer is approximately 35 C.

Answer 2

This question is from an NES study guide and the guide claims the answer is 37, but when i did the math I got 37.6 and am confused why this would round down to 37.0 instead of up to 38.0.